Background Community iron supplementation programmes for pregnant women have lacked effectiveness, partly because of low compliance.

Objective To determine factors that influence compliance among pregnant women in Senegal.

Design Two hundred and twenty-one pregnant women, recruited from six health centres in Dakar during their first prenatal visit, were randomly assigned to receive either a prescription to purchase iron/folic acid tablets (control, n = 112) to be taken daily, according to official policy, or to receive free tablets (treatment, n = 109). Compliance was assessed 20 weeks after enrolment through interviews and pill count. Women with low or high compliance (<70% or ≥70%) were asked to explain what influenced their adherence to supplementation.

Results Overall compliance was 69%; it was significantly higher in the treatment than in the control group (86% vs. 48%; P < 0.0001). Women with high compliance (58%) were motivated by: (1) the perception of improved health upon taking the tablets (treatment = 24%, control = 10%); (2) the insistence by midwives that they take the tablets; and (3) the mention that the tablets would improve health. Women with low compliance (42%) reported: (1) the experience of side-effects that they associated with the tablets (treatment = 13%, control = 14%); (2) misunderstanding that they needed to continue taking the tablets throughout pregnancy (treatment = 0%, control = 18%); and (3) forgetfulness.

Conclusion Compliance with iron/folic acid supplementation in Senegal can be increased by providing women with clear instructions about tablet intake and educating them on the health benefits of the tablets.